Glass furnace



L mass of material. The glass-producingbatch Patented Dec. Y 18, 1928.

'WIJ'.IIIJAMI K. BROWNIEE: OF TOLEDO, OHIO, IASSIGN'OIR.

PATENT OFFICE. I

GLASS COMP N Y, OF TOLEDO, OHIO, A CORPORATION OF OHIO. i

At the melting end of this tank a series of gas.-

flames play upon the surface of the molten and cullet are inserted at. this end of the furnace and after being melted flow slowly through theitank toward the sheet-drawing. machine. It is necessary for the molten glass to be refined or settled until it reaches the required state of plasticity and homogeneity before being drawn into glass sheets. The entire tank is enclosed suo that the surface lass is always exposed to a heated atmosp ere, but usually no further heat `is applied after the glass passes beyond themelting endof the tank. As the lass llows through the socalled reiiningl endof the tank, the surface glass loses some heat but still retains a rather high'temperature. In the form .of tank disclosedin the Colburn patent above noted, the glass flows through a smaller cooling charnber intermediate the reinin tank and the draw-pot. I This cooling ta in which the refining and cooling process is continued, is much shallower than the refining tank and the arched chamber above is lower.v

lWhile this molten glass vis passing through the refining and cooling tanks, the lower strata of the glass lose a-greatdeal of heat which is conducted andradiated awa by the enclosing walls of the' tanks. In this way the lower and side portions of the moltenglass becomes cooler and stiffer, and tend to stagnate, so that the greater portion ofthe flow is .confined to the. surfaceglass This 'retardation 'of the lower and side strata is' also, caused by the friction of the owing glass against the Walls and bottom of thev tank. This limitation of the iiow to the surface strata. greatly decreases the producing capacity of the tank, and consequently the rate at Application led Hay l 21,

GLASS FUBNACE. 'J

192s. serial mi. 640,847.

Iwhich sheet glass can be successively drawn therefrom. It is also objectionable to have 'ro 'r1-:ti: LIBBnY-owENssnnn-T' semi-stagnant glass in the tank which loses IJits proper consistency and tends to devitrify. The object of the present invention is to -so vary the tank 'construction-that the molten glass will maintain a more nearly equal temf' perature from top to bottom, and the How will be more uniform and not tothe surface strata. This partly by adding insulatio'ns around the deeper portions of the refining tank to de-l confned merely is accomplished Acreasethe heat loss in this portion of the furnace,gand partly by positively heating ythe shallower tank portion between the .refining tank and the drawing point for the sheet.

The invention will be more clearly under.- stood from the following drawings and de-y form of the apparatus.

In the accompanying drawings:

.tailed description disclosing one approved Fig; 1 is a vertlcal longitudinal section through the portions of the sheet drawing apparatus' and furnace that have been I changed to embody the principles of this invention.

- Fig. 21s a transverse vertical section taken.:

substantially on the line II-II of Fig. 1.- f

As in the Colburn patent noted above', the l glass sheet 1 is drawn upwardly from the shallow receptacle or draw-pot 2, deflectedover bending roll 3 and carried away through drawing and iattening mechanism 4 into the leer. .Alll of this structure and operation is well ,knorwn in the art'and may be ascertained in detall from the Colburn patent, l noted above. As in this Colburn patent, aiheating stools 6 witin the furnace. The heating gases enter through ports 7 and 8 and after pot 2 pass out through flue 9 and under cover tile 10 above the closed end of the pot.`

'At 11 is shown the delivery end of.the re'- lining tank which is merely a prolongation lfurnace 5 is located beneath the draw-potflQ, which 'is su ported'onr suitable arches'rl -of the melting tank in which the lass-produc-ing materials are reduced to mo ten lass.

This refining tank 11 is housed by the c am- .ber 12 .which isa continuation of the meltingk chamber andlconfines a highly heated atmoshere abovefthesurface'of the molten glass. The surface glass 13 will Lcool somewhat but will bejretained at a relatively high temperapassing around the bottom andsides of the ture by the heated atmosphere above. However, the lower strata 14,0f the molten glass in this chamber will ordinarily lose consider'- able heat which is conducted and radiated awayby the walls of the tank 11. In tanks now in use there will 'normally be a loss of about 100 F. to each foot of depth in this tank. To decrease the heat loss at this point, the refining tank in this new construction is surrounded with walls of suitable insulating material, these walls being thicker toward the lower portion of the tank where 'the heat loss is the greatest. As illustrated, the

greater portion of the tank 11 is enclosed with a layer of fire brick 15. The lower portions of the tank are'further surrounded with one I or more layers of suitable insulating bricks or4 blocks. An excellent material for this purpose is known as silocel, whose basis is kieselguhr. The insulating walls may be constructed of slocel bricks united into solid walls rial. p

From the refining tank 11, the molten glass flows through an'intermediate shallow tank by a cement formed of the 'same matel 17 to the draw-pot 2. This tank is enclosed by a lower arched housing 18, commonly known as the cooling chamber, although the temperature in this chamber is also quite hot, as the chamber is in communication with the heated chamber 12. Preferably 'an adjustable gate 19 is provided between these two chambers to regulate to someextent the of the shallow stream of molten glass that onl the upper strata flow freely through the tan thus greatly diminishing the volume and depth of the molten glass` delivered to the draw-pot 2. i

In the improved construction herewith disclosed, the tank 17 is substantially a continuation of the draw-pot 2 and is mounted over and carried by a second heating furnace 20, somewhat similar to the one shown at 5 for heating the draw-pot 2. The tank 17, like the draw-pot 2, is molded as a single unit from fire-cla' or similar material. In this furnace 20, t e burners 21 deliver their heat through ports 22 to the chambers 23 at the tWof-ends of the furnace. These -chambers 23 are formedA by the supporting partitions 24 whichl extend `part way from the side walls of the furnace toward the center ofthe tank 17 leaving a passage 25 between their `inner edges through which the heated gases pass to a central chamber 26. Some portions of Ythe heated gases also pass from chambers 23 \to the central chamber 26 through the passages 27 formed by cutting away portions of the tank-supporting upper edges of the partitions 24. The heated gases and products of combustion are drawn out from the central chamber 26 through the iues 28. fIt is to be understood that the furnace here shown is merely' one example of many that might be used'for supporting and heating the tank 17. It will be noted that this furnace also encloses the side portions 29 of the tank `as at l30, to heat the molten glass adjacent the sides of the tank. A chilling water pipe 31 is placed below the joint 32 between tanks 2 and 17v to prevent leakage at this point. It

,will also be observed lthat a ,cooling space 33 is left between the two rnaces 5 and 20, so as to assist in cooling th joint 32. A similar cooling pipe 34 is placed below the connection between tank 17 and refining tank 11.

In this improved construction, as the moll ten glass flows slowly through refining tank 11, the loss of heat from the lower strata of vthe molten glass will be greatly reduced by the insulation walls 1,5 and 16. VAs the glass flows into and through the tank 17, the lower and side strata of this glass will be positively heated from thefurnace 20 so that the temperature of the lower strata will be raised as high or higher than that of the surface glass. 9

This will not only increase the fluidity of the lower strata so that they will flow more freely, but will also lubricate the side and bottom walls of the tank 17 to reduce the friction and permit a freer passage of the glass through Vthe tank. As aresult, a more uniform flow of lass is delivered to the draw-pot or receptac e 2 throughout substantially the entire depth of the glass in this receptacle. It is necessary to use a somewhat more intense cooling means at 35, or provide a larger eX- posed area of the surface glass adjacent the sheet source, than has been the prior ractice, to Vcompensate for the somewhat hig er temperature of the glass delivered to the draw point. By employing this greatercoolingmeans and the larger volume of ilow of molten glass to the pot 2, the sheet 1 may be drawn at a much more rapid rate than has been the prior practice, thus greatly increasing the production and eiliciency of the machine.

1. In the art of drawing sheet glass, the method of supplying molten glass to the pool from which the sheet is drawn, consisting in melting the lass producing materials, flowing the mol through a refining and cooling chamber, and

simultaneously heating the lower strata and side portions of the flowing glass. L

2. In the art of drawing sheet glass, the method of supplying molten glass to the pool from which the sheet is drawn, consistin 1nmelting the glass producing materials, ow-

ten glass to the sheet source l no ing the molten glass to the sheet source through a refining and cooling chamber, and simultaneously heating the lower lstrata and side portions of the flowing glass, without adding heat to the surface strata.

` 3. In the art of drawing sheet glass, the step of applying heat to the lower strata and side portions of the fiow of molten glass to the sheet source to compensate for ,the heat normally conducted and radiated away by the fining tank.

5. In a sheetglass drawing apparatus, the combination with a receptacle fora pool of molten glass, means for drawing a glass sheet therefrom, and a melting tank wherein the molten glass is produced, of a comparatively deep refining tank, and a comparatively shallow refining tank through which tanks the molten'glass passes successively to the receptacle, a wall of insulating material confining the lower portions of the deeper tank, and a heating furnace beneath the shallower. tank and the receptacle.

6. In a sheet glass drawing apparatus, a

refining tank through which the molten glass passes, a housing confining a heated atmosphereabove the tank, and a heating furnace surrounding the bottom and sides of the tank. 7. In a sheet glass drawing apparatus, the combination with a melting tank, of a pair of similar shallow tanks or receptacles arranged in open communication with one another, the molten glass flowing from the melting tank through one of the receptacles into the other, means` for drawing glass in sheet form from the latter receptacle, an enclosing chamber above the first namedl shallow receptacle, and heating means beneath both of the shallow receptacles. 8. In a sheet glass drawing apparatus, the combination with a melting tank, ofa pair of similar shallow tanks or receptacles arranged in open communication with one another, the molten glass flowing from the melting tank through one of the receptacles into the other, means for drawing glass in sheet form from the latter receptacle, an enclosing chamber above the first named shallow receptacle, and a separate heating chamber beneath each of the shallow receptacles.

Signed at Toledo, in the county of Lucas, and State of Ohio, this 16th day of May. 1923.

WILLIAM K. BROWNLEE. 

